Money, party loyalty and a nagging belief that the Republican nomination is still his to win are keeping John B. Anderson from launching an independent bid for the White House.

If Anderson chooses that route to the presidency, his deeply divided advisers say, it is now most likely he would not do so until after the Republican National Convention in July. But events have moved so quickly in the last two weeks that they say a decision could come sooner, possibly by early May.

"The real fail-safe point is after the convention," said Michael MacLeod, Anderson's campaign manager. "There are any number of junctures between now and then when some action could be taken."

Anderson and MacLeod went over the options for an independent candidacy -- including one ruling out such a bid -- for the first time during a strategy session Tuesday in Wisconsin. But they stopped far short of any firm decisions. One reason is that despite the "urgings" the Illinois congressman is getting to bolt the party, "we have no accurate fix on how profound the sentiment is for an independent bid," MacLeod said.

"Ronald Reagan doesn't have it locked up," said Cliff Brown, Anderson's research director. "He's damn close. But if he starts losing some of these primaries, it's going to collapse."

Anderson's advisers believe that Reagan's money problems -- he has spent more than two-thirds of the amount allowed by law for the nominating process -- will contribute to the former California governor's decline.

With that in mind, Anderson and MacLeod agreed Tuesday that after next week's primaries in Wisconsin and Kansas, Anderson will concentrate on two things: Keeping Reagan from winning a majority of the delegates in the April 22 Pennsylvania primary and winning the May 6 winner-take-all Indiana primary.

Anderson is expected to devote most of his own time to Indiana, where his advisers now hope he can start a winning streak that will climax with victories in California, Ohio and New Jersey on June 3. Anderson's strategists believe that would give him the nomination.

Only after Anderson becomes personally convinced that he can't beat Reagan -- and that could come after the first round of primaries in May, especially if he loses Wisconsin next Tuesday -- is he likely to think about starting an independent candidacy. Even then he may decide to carry his campaign to the GOP convention in Detroit.

"He is a Republican, he has been all his life," said Daniel Swillinger, a consultant to the campaign. "Going the independent route would be a rejection of the past year's aggravation. He feels he's put in an awful lot of energy and that he ought to see it through."

Going to the convention and being nominated also would keep alive the symbolism of the crusade he has been leading within the party, and bring him more media attention.

Most of Anderson's top advisers come from the liberal wing of the party and many worked for the Ripon Society. They share Anderson's goal of broadening the party's base and still dream of talking control away from the conservatives, who have dominated since 1964, when Barry Goldwater was the presidential nominee. Most of them won't even describe an independent candidacy as a "third party" bid, emphasizing instead Anderson's and their own Republican credentials.

The one person in the campaign described as most favorable to an independent bid is Anderson's advertising man, R. J. Sann of New York.The other senior advisers are still wrestling personally with the idea. As a result there is no consensus among the staff on the advisability or the timing of an independent bid.

"The staff input is essentially factual," said one member of the staff. "The decision will be made by one person, Anderson, not the staff as a whole. The only unanimous feeling is that whatever he decides to do, the staff will enthusiastically support him."

Anderson and his advisers are not particularly worried now that delaying a decision reduces the number of states where he could get on the ballot as an independent. Even after the Republican convention, he could run in more than 30 states that account for more than 300 electoral college votes (270 are needed for election).

Nor is Anderson likely to make a decision based on the numbers. "He got into the race not with this Himalaya complex of climbing the mountain because it's there but because of the issues he believes in," MacLeod said. "So far the process has not served up leaders of sufficient stature to deal with them. That whole 'country above politics' theme is of abiding concern to him."

The biggest technical obstacle to an immediate indpendent candidacy -- or even one later this year -- is money. "The minute he announces, his federal matching funds end," said one adviser, "and he's got to go out and raise new money." He would be denied the $29.4 million in public funds available to the Republican and Democratic nominees for the general election campaign.

Anderson now has a contributor base of about 70,000 persons (George Bush has about 61,000), compared to 4,000 on Jan. 1. And his fund-raisers report that the flood of responses to direct mail appeals has not slowed.

"We're picking up between 2,000 and 5,000 new donors a day," said Rob Smith. "Very shortly he will have one of the largest donor constituencies of any campaign in the last 10 years. It's building at a pace almost akin to the McGovern constituency in 1972 and today there's not a war on."

But Anderson's advisers wonder whether the flood would continue for an independent candidate -- or in enough volume to make it financially possible to run such a campaign. "It's an uncharted field," said one.

Which is why there is more comfort now in believing the GOP nomination can be taken away from Ronald Reagan, and putting off a decision until later. c